CN112352031A - Quantum dot LED design based on resonance energy transfer - Google Patents

Quantum dot LED design based on resonance energy transfer Download PDF

Info

Publication number
CN112352031A
CN112352031A CN201980040310.7A CN201980040310A CN112352031A CN 112352031 A CN112352031 A CN 112352031A CN 201980040310 A CN201980040310 A CN 201980040310A CN 112352031 A CN112352031 A CN 112352031A
Authority
CN
China
Prior art keywords
layer
conductive layer
quantum dots
transport layer
core
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201980040310.7A
Other languages
Chinese (zh)
Inventor
E·R·唐纳
Y·A·乔
C·J·伊彭
J·T·蒂尔曼
J·A·特拉斯基尔
郭文卓
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shoei Chemical Inc
Original Assignee
Nanosys Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanosys Inc filed Critical Nanosys Inc
Publication of CN112352031A publication Critical patent/CN112352031A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C09K11/025—Use of particular materials as binders, particle coatings or suspension media therefor non-luminescent particle coatings or suspension media
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C09K11/562—Chalcogenides
    • C09K11/565—Chalcogenides with zinc cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/62—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing gallium, indium or thallium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/70—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/70—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus
    • C09K11/701—Chalcogenides
    • C09K11/703—Chalcogenides with zinc or cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • C09K11/881—Chalcogenides
    • C09K11/883—Chalcogenides with zinc or cadmium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/08—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/08—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H01L33/24—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate of the light emitting region, e.g. non-planar junction
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/52—Encapsulations
    • H01L33/56—Materials, e.g. epoxy or silicone resin
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/40—Thermal treatment, e.g. annealing in the presence of a solvent vapour
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/331—Nanoparticles used in non-emissive layers, e.g. in packaging layer

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Nanotechnology (AREA)
  • Electroluminescent Light Sources (AREA)
  • Luminescent Compositions (AREA)

Abstract

Embodiments of the present application relate to lighting devices using light emitting nanostructures. The lighting device includes a first conductive layer, a second conductive layer, a hole transport layer, an electron transport layer, and a material layer comprising a plurality of light emitting nanostructures. The hole transport layer and the electron transport layer are each disposed between the first conductive layer and the second conductive layer. The material layer is disposed between the hole transport layer and the electron transport layer and includes one or more discontinuities in its thickness such that the hole transport layer and the electron transport layer contact each other at the one or more discontinuities. Resonance energy transfer occurs between the light emitting nanostructure and the exciton at the discontinuity.

Description

Quantum dot LED design based on resonance energy transfer
Technical Field
The present application relates to quantum dot emission technology, and to lighting devices using quantum dots.
Background
Semiconductor nanocrystals (quantum dots) with radii smaller than the bulk exciton bohr radius constitute a class of materials that is intermediate between the molecular and bulk forms of matter. Quantum confinement of electrons and holes in all three dimensions results in an increase in the effective band gap of the material, reducing the crystallite size. Therefore, as the size of the quantum dot becomes smaller, both the optical absorption and emission of the quantum dot move to blue (higher energy). The introduction of quantum dots in display devices such as LCDs has been shown to produce highly vivid colors while reducing overall power consumption. Quantum dots provide desirable characteristics due to their low power consumption, low manufacturing cost, and highly vivid light output.
Recently, quantum dots have been introduced into light emitting diodes (QD-LEDs), in which an emission layer containing quantum dots has both electrons and holes injected therein, thereby exciting the energy states of the quantum dots. The External Quantum Efficiency (EQE) of CdSe-based red QD-LEDs is reported to exceed 20%, approaching the theoretical limit for QD-LED efficiency. In contrast, the EQE reported for the most InP based QD-LEDs is only 2.3% (red) and 3.5% (green). This difference may be due in part to the quenching that InP quantum dots exhibit when deposited into close-packed films. One approach to combat the low quantum yield of quantum dots is to increase the shell thickness around the core material. However, increasing the shell thickness also increases the potential barrier for injecting and transporting charge into and between the quantum dots, requiring higher voltages to reach the relevant brightness levels. These high operating voltages result in power inefficiencies and reduced stability of the device.
Disclosure of Invention
Embodiments of the present application relate to devices using quantum dots having both improved quantum yield and relatively low operating voltage.
According to one embodiment, a lighting device includes a first conducting layer, a second conducting layer, a hole transport layer, an electron transport layer, and a plurality of light emitting nanostructures. The hole transport layer and the electron transport layer are each disposed between the first conductive layer and the second conductive layer. In one embodiment, the plurality of light emitting nanostructures are disposed in a separate layer between the electron transport layer and the hole transport layer, the separate layer having a plurality of discontinuities through a thickness of the separate layer such that the hole transport layer and the electron transport layer contact each other at the plurality of discontinuities. The discontinuities may form a random or regular pattern. In another embodiment, a plurality of light emitting nanostructures are disposed in the electron transport layer. In another embodiment, a plurality of light emitting nanostructures are disposed in the hole transport layer. In another embodiment, the plurality of light emitting nanostructures are disposed in a mixed layer comprising both a hole transport layer and an electron transport layer.
According to another embodiment, a QD-LED device includes a layer stack having a first conducting layer, a second conducting layer, a hole transporting layer, an electron transporting layer, and a layer comprising a plurality of quantum dots. The hole transport layer and the electron transport layer are each disposed between the first conductive layer and the second conductive layer. In one embodiment, the plurality of quantum dots are disposed in a separate layer between the electron transport layer and the hole transport layer, the separate layer having a plurality of discontinuities through a thickness of the separate layer such that the hole transport layer and the electron transport layer contact each other at the plurality of discontinuities. The discontinuities may form a random or regular pattern. In another embodiment, a plurality of quantum dots are disposed in the electron transport layer. In another embodiment, a plurality of quantum dots are disposed in the hole transport layer. In another embodiment, the plurality of quantum dots are disposed in a mixed layer that includes both a hole transport layer and an electron transport layer. The QD-LED device also includes a first contact coupled to the first conductive layer, a second contact coupled to the second conductive layer, and an encapsulation material surrounding the layer stack.
One example method of forming a lighting device includes disposing a first material on a conductive substrate to form a first material layer, wherein the first material layer is a hole transport layer or an electron transport layer. The method also includes disposing a layer of light emitting nanostructures on the first layer of material. The layer of light emitting nanostructures includes a plurality of discontinuities in a thickness of the layer of light emitting nanostructures. The method also includes disposing a second material on the layer of light emitting nanostructures to form a second material layer, wherein the second material is an electron transport layer or a hole transport layer. The second material layer is in contact with the first material layer at the plurality of discontinuities of the layer of light emitting nanostructures. The method also includes disposing a conductive material on the second material layer.
Another example method of forming a lighting device includes disposing a first material on a conductive substrate to form a first material layer, wherein the first material layer is a hole transport layer. The method also includes disposing a second material on the first material layer to form a second material layer, wherein the second material layer is an electron transport layer and includes a plurality of light emitting nanostructures. The method also includes disposing a conductive material on the second material layer.
Another example method of forming a lighting device includes disposing a first material on a conductive substrate to form a first material layer, wherein the first material layer is a hole transport layer and includes a plurality of light emitting nanostructures. The method also includes disposing a second material on the first material layer to form a second material layer, wherein the second material layer is an electron transport layer. The method also includes disposing a conductive material on the second material layer.
Another example method of forming a lighting device includes disposing a mixed material layer on a conductive substrate, wherein the mixed material layer includes an electron transport material, a hole transport material, and a plurality of light emitting nanostructures. The method also includes disposing a conductive material on the mixed material layer.
Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Other embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein.
Drawings
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the embodiments and to enable a person skilled in the pertinent art to make and use the embodiments.
Figure 1 illustrates a standard LED structure using luminescent nanoparticles.
FIG. 2 illustrates an LED structure using luminescent nanoparticles according to one embodiment.
FIG. 3 illustrates another LED structure using luminescent nanoparticles according to one embodiment.
FIG. 4 illustrates another LED structure using luminescent nanoparticles according to one embodiment.
FIG. 5 illustrates a packaged LED device using light emitting nanostructures according to one embodiment.
Fig. 6 illustrates a flow chart of an exemplary method of manufacturing a lighting device according to one embodiment.
Fig. 7 is a schematic diagram of a cross-sectional view of a nanostructure according to an embodiment.
Fig. 8 is a schematic of a nanostructured film according to one embodiment.
Fig. 9A and 9B illustrate device characteristics of LED devices using light emitting nanostructures according to some embodiments.
Fig. 10 is a Scanning Electron Microscope (SEM) image of a portion of an illumination device according to an embodiment.
The features and advantages of embodiments of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.
Detailed Description
While specific configurations and arrangements may be discussed, it should be understood that this is done for illustrative purposes only. One skilled in the relevant art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the invention. It will be apparent to those skilled in the relevant art that the present invention may be used in a variety of other applications beyond those specifically mentioned herein.
It should be noted that references in the specification to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
Unless otherwise expressly indicated, all numbers in this description indicating amounts of material, ratios of materials, physical properties of materials and/or use are to be understood as modified by the word "about".
Terms used herein
In an embodiment, the term "display device" refers to an arrangement of elements that allows data to be visually presented on a display screen. Suitable display screens may include various flat, curved, or other shaped screens, films, sheets, or other structures for visually displaying information to a user. The display devices described herein may be included in, for example, a display system, including a Liquid Crystal Display (LCD), a television, a computer, a mobile phone, a smartphone, a Personal Digital Assistant (PDA), a gaming device, an electronic reading device, a digital camera, a tablet, a wearable device, a car navigation system, and so forth.
As used herein, the term "about" refers to a change in a given amount of a value by ± 10% of the value. For example, "about 100 nm" encompasses a range of sizes from 90nm to 110nm, inclusive.
As used herein, the term "substantially" means that the value of a given quantity varies between ± 1% to ± 5% of the value.
In embodiments, the term "forming a reaction mixture" or "forming a mixture" refers to combining at least two components in a vessel under conditions suitable for the components to react with each other to form a third component.
As used herein, the term "nanostructure" refers to a structure having at least one region or characteristic dimension that is less than about 500nm in size. In some embodiments, the nanostructures have a dimension of less than about 200nm, less than about 100nm, less than about 50nm, less than about 20nm, or less than about 10 nm. Typically, the region or characteristic dimension will be along the smallest axis of the structure. Examples of such structures include nanowires, nanorods, nanotubes, branched nanostructures, nanotopods, tripods, bipods, nanocrystals, nanodots, QDs, nanoparticles, and the like. The nanostructures may be, for example, substantially crystalline, substantially single crystalline, polycrystalline, amorphous, or a combination thereof. In some embodiments, each of the three dimensions of the nanostructure has a size of less than about 500nm, less than about 200nm, less than about 100nm, less than about 50nm, less than about 20nm, or less than about 10 nm.
As used herein, the term "QD" or "nanocrystal" refers to a substantially single crystalline nanostructure. Nanocrystals have at least one region or characteristic dimension that is less than about 500nm in size and down to the order of less than about 1 nm. Those of ordinary skill in the art will readily appreciate that the terms "nanocrystals," "QDs," "nanodots," and "dots" represent the same structure and are used interchangeably herein. The invention also encompasses the use of polycrystalline or amorphous nanocrystals.
The term "heterostructure" when used in reference to a nanostructure refers to a nanostructure characterized by at least two distinct and/or distinguishable material types. Typically, one region of the nanostructure comprises a first material type and a second region of the nanostructure comprises a second material type. In certain embodiments, the nanostructures comprise a core of a first material and at least one shell of a second (or third, etc.) material, wherein the different material types are distributed radially around, for example, the major axis of the nanowire, the long axis of the arms of the branched nanowire, or the center of the nanocrystal. The shell may, but need not, completely cover the adjacent material to be considered a shell or to make the nanostructure considered a heterostructure; for example, nanocrystals characterized by a core of one material covered with small islands of a second material are heterostructures. In other embodiments, different material types are distributed at different locations within the nanostructure; for example, along the major (long) axis of the nanowire or along the long axis of the arm of the branched nanowire. Different regions within a heterostructure may comprise disparate materials or different regions may comprise a base material (e.g., silicon) with different dopants or different concentrations of the same dopant.
As used herein, the "diameter" of a nanostructure refers to the diameter of a cross-section perpendicular to a first axis of the nanostructure, where the first axis has the greatest difference in length relative to second and third axes (the second and third axes being the two axes having lengths that are the closest equal to each other). The first axis is not necessarily the longest axis of the nanostructure; for example, for a disc-shaped nanostructure, the cross-section would be a substantially circular cross-section perpendicular to the short longitudinal axis of the disc. In the case where the cross-section is not circular, the diameter is the average of the major and minor axes of the cross-section. For elongated or high aspect ratio nanostructures, such as nanowires, the diameter is measured in a cross-section perpendicular to the longest axis of the nanowire. For spherical nanostructures, the diameter is measured from side to side through the center of the sphere.
The term "crystalline" or "substantially crystalline" when used in reference to a nanostructure refers to the fact that the nanostructure typically exhibits long-range order in one or more dimensions of the structure. It will be understood by those skilled in the art that the term "long-range order" will depend on the absolute size of the particular nanostructure, since the order of a single crystal cannot extend beyond the boundaries of the crystal. In such cases, "long-range order" will refer to substantial order in at least a majority of the dimensions of the nanostructure. In some cases, the nanostructures may bear an oxide or other coating, or may be composed of a core and at least one shell. In such cases, it is understood that the oxide, shell(s), or other cladding layer may, but need not, exhibit such ordering (e.g., it may be amorphous, polycrystalline, or otherwise). In such cases, the expressions "crystalline," "substantially monocrystalline," or "monocrystalline" refer to the central core (excluding the coating or shell) of the nanostructure. As used herein, the term "crystalline" or "substantially crystalline" is intended to also encompass structures comprising various defects, stacking faults, atomic substitutions, and the like, so long as the structure exhibits substantial long-range order (e.g., order over at least about 80% of the length of at least one axis of the nanostructure or core thereof). In addition, it is understood that the interface between the core and the exterior of the nanostructure, or between the core and an adjacent shell, or between the shell and a second adjacent shell, may contain amorphous regions and may even be amorphous. This does not preclude the nanostructures from being crystalline or substantially crystalline as defined herein.
The term "monocrystalline" when used with respect to a nanostructure indicates that the nanostructure is substantially crystalline and comprises substantially single crystals. When used with respect to a nanostructure heterostructure comprising a core and one or more shells, "monocrystalline" indicates that the core is substantially crystalline and comprises substantially single crystals.
As used herein, the term "ligand" refers to a molecule capable of interacting (weakly or strongly) with one or more faces of a nanostructure, for example, by covalent, ionic, van der waals forces, or other molecular interactions with the surface of the nanostructure.
As used herein, the term "quantum yield" (QY) refers to the ratio of photons emitted to photons absorbed, e.g., by a nanostructure or population of nanostructures. As is known in the art, quantum yield is typically determined by comparative methods using well-characterized standard samples with known quantum yield values.
As used herein, the term "dominant emission peak wavelength" refers to the wavelength at which the emission spectrum exhibits the highest intensity.
As used herein, the term "full width at half maximum" (FWHM) refers to a measure of the spectral width. In the case of an emission spectrum, FWHM may refer to the width of the emission spectrum at half the peak intensity value.
The term foster radius as used herein is also known in the art as foster distance.
The terms "luminosity" and "brightness" are used interchangeably herein and refer to a photometric measurement of the luminous intensity of a light source or illuminated surface per unit area.
As used herein, the term "radiance" refers to a measure of the intensity of radiation per unit area of a light source or illuminated surface.
The term "Nanostructure (NS) film" is used herein to refer to a film having luminescent nanostructures.
As used herein, the term "luminosity" refers to the intensity of light per unit area of the emitting surface.
The published patents, patent applications, web sites, company names and scientific literature referred to herein are incorporated by reference in their entirety to the same extent as if each was specifically and individually indicated to be incorporated by reference. Any conflict between any reference cited herein and the specific teachings of this specification shall be resolved in favor of the latter. Likewise, any conflict between a definition in the art of a word or expression and that of the word or expression as specifically taught in this specification shall be resolved in favor of the latter.
Unless defined otherwise, technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this application belongs. Reference is made herein to various methods and materials known to those skilled in the art.
SUMMARY
The present disclosure provides various embodiments of nanostructure-based Light Emitting Diodes (LEDs) that may be used in display devices. In some embodiments, the LEDs include Quantum Dots (QDs) that exhibit relatively high quantum yields compared to the relatively low operating voltages of the LEDs. Various embodiments of structures of QD-LEDs and methods of making the same are described herein.
Nanostructure-based LED design
Fig. 1 illustrates one example of an LED device 100 using light-emitting nanostructures as a light-generating medium. The LED device 100 includes a stacked configuration of different layers to provide a voltage across a polymer layer containing a plurality of light emitting nanostructures, such as quantum dots. If quantum dots are used as the light emitting nanostructures, the LED device 100 may be referred to as a QD-LED device. The LED device 100 comprises a first conductive layer 102 on which a stack of further layers is formed. The first conductive layer 102 may be a transparent conductive material, such as Indium Tin Oxide (ITO). Depending on the configuration of the further layers, the first conductive layer 102 may act as an anode or a cathode of the LED device 100. In examples where the LED device 100 includes an electron transport layer 104 on the first conductive layer 102, the first conductive layer 102 serves as the cathode of the LED device 100.
The electron transport layer 104 is designed to inject electrons under an applied electric field into a material layer 106 comprising a plurality of light emitting nanostructures. Similarly, under the same applied electric field, the hole transport layer 108 injects holes into the material layer 106. An electric field is applied between the first conductive layer 102 and a second conductive layer 112 formed at the top of the layer stack. The second conductive layer 112 may comprise a metal, such as aluminum, gold, or silver, and may serve as an anode of the LED device 100. In some examples, each of first conductive layer 102 and second conductive layer 112 is substantially transparent to visible light. The light emitting nanostructures in the material layer 106 will become electroluminescent when charge injected through the opposite side of the material layer 106 recombines (recombine) to produce an emission characteristic for the band gap or trap site. Some examples of LED device 100 also include a hole injection layer 110 designed to facilitate hole injection from the anode into hole transport layer 108.
Examples of light emitting nanostructures include quantum dots having a semiconductor core material with a direct or near direct band gap. Examples of QD core materials include various III-V semiconductor compounds such as indium phosphide (InP), cadmium selenide (CdSe), and gallium arsenide (GaAs). The semiconductor core is often surrounded by a shell material having a wide band gap. One example shell material is zinc selenide (ZnSe). Further details regarding the colloidal growth and composition of QDs to be used within the QD-LED structure will be discussed herein with reference to fig. 9-10.
The light-emitting nanostructures within the material layer 106 may be suspended in a material that is substantially transparent to visible light. The material layer 106 may comprise a polymer that encapsulates and protects the light emitting nanostructures suspended therein. Example materials for use in the material layer 106 include acrylates, epoxies, acrylated epoxies, ethylene vinyl acetate, thiol-enes, polyurethanes, polyethers, polyols, and polyesters. In one example, the light emitting nanostructures are mixed in an amino silicone fluid and emulsified into an epoxy resin, which is coated to form the material layer 106. For more details on the fabrication and operation of quantum dot enhanced films, one example of a material layer 106 can be found in U.S. patent No. 9,199,842, the disclosure of which is incorporated herein by reference.
In a typical QD-LED structure, injection of electrons and holes into the material layer 106 excites the QDs present in the material layer 106, and thus a sufficiently high activation voltage is required to penetrate the shell structure. While thicker shells will provide better environmental protection for the QDs and improve quantum yield, they also require higher activation voltages, resulting in higher power consumption and poorer overall efficiency.
According to some embodiments, LED structures are described that utilize different mechanisms to excite light emitting nanostructures (e.g., quantum dots). Instead of using direct carrier injection to excite the light emitting structure, the light emitting nanostructure is excited by the transfer of resonance energy generated by the generation of excitons in the adjacent electron transport layer. Resonance energy transfer forms excitons on the core of the light-emitting nanostructure, which then recombine radiatively (e.g., as generated light).
FIG. 2 illustrates an example of an LED structure 200 utilizing light emitting nanostructures according to one embodiment. Many of the layers of the LED structure 200 share the same labels as the layers of the LED structure 100 and/or are functionally similar to the layers of the LED structure 100. For clarity, these layers will not be described again. According to one embodiment, the LED structure 200 includes a material layer 202 having a plurality of light emitting nanostructures, such as quantum dots. The material layer 202 may be formed very thin, e.g., less than a few monolayers thick, or only a single monolayer thick, where a monolayer may be about 10nm thick. According to one embodiment, the low thickness of the material layer 202 facilitates forming discontinuities 204 through the thickness of the material layer 202. The discontinuities 204 may have any shape or pattern. In some examples, the discontinuities 204 are randomly interspersed on the surface of the material layer 202. In other examples, the discontinuities 204 are formed in a particular pattern, or encouraged to be formed using one or more application techniques, such as etching. In another example, the material layer 202 can be formed by spin coating a solution containing a dilute concentration of light emitting nanostructures to facilitate the formation of discontinuities.
Due to the presence of the discontinuity 204, the electron transport layer 206 and the hole transport layer 208 are in contact with each other via the discontinuity 204. When the deposition of the hole transport layer 208 on the material layer 202 is also deposited within the discontinuities 204, contacts may be made to contact the underlying electron transport layer 206. Such an electrical "short-circuit" between the electron and hole transport layers is conventionally avoided, since in this case no (or very little) current is carriedThe ions are implanted into the material layer 202. However, direct contact between the electron transport layer 206 and the hole transport layer 208 allows holes to be injected into the intermediate bandgap defect state in the electron transport layer 206, thereby combining with electrons injected from the cathode to form excitons. Due to the proximity between the light emitting nanostructure and the excitons generated in electron transport layer 206, the excitons transfer energy to the light emitting nanostructure in a resonant manner, resulting in efficient emission from the light emitting nanostructure with little or no parasitic emission from the defect state of electron transport layer 206. The use of zinc magnesium oxide (ZnMgO) as an electron transport layer or of materials comprising ZnMgO nanoparticles as an electron transport layer has been shown to provide efficient energy transfer between the formed excitons and the light emitting nanostructure. This can be attributed to certain properties of the ZnMgO nanoparticles, such as their energy distribution, slow radiation decay, and relatively high quantum yield. Some examples of materials for the hole transport layer 208 include those commonly used in OLEDs such as 9, 9-dioctylfluorene/N- (4-sec-butylphenyl) -diphenylamine alternating copolymer (TFB) and N, N '-di (1-naphthyl) -N, N' -diphenyl- (1,1 '-biphenyl) -4, 4' -diamine (NPB). Some examples of inorganic materials for the hole transport layer 208 include copper oxide (Cu)2O) or copper gallium oxide nanoparticles (Cu)xGa1-xO)。
It is understood that the order of depositing layers to form the LED structure 200 may be reversed. In other words, according to one embodiment, the material layer 202 may be formed on the hole transport layer 208 and the electron transport layer 206 deposited on the material layer 202 to contact the underlying hole transport layer 208 via the discontinuity 204.
FIG. 3 illustrates another example of an LED structure 300 utilizing light emitting nanostructures according to one embodiment. Many of the layers of the LED structure 300 share the same labels as the layers of the LED structure 100 and/or are functionally similar to the layers of the LED structure 100. For clarity, these layers will not be described again. According to one embodiment, the LED structure 300 includes a mixed layer 302 that includes both the electron transport material and the light emitting nanostructure in the same layer. For example, the mixed layer 302 may include a mixture of ZnMgO nanoparticles and QDs. The proximity of the QDs mixed with the electron transport material allows resonance energy transfer to occur between the QDs and the excitons formed. In another embodiment, the mixed layer 302 includes both hole transporting material and light emitting nanostructures, and the hole transporting layer 108 is replaced with an electron transporting layer. The hole injection layer 110 can also be moved so that it is adjacent to the mixed layer 302 having both the hole transport material and the light emitting nanostructure.
FIG. 4 illustrates another example of an LED structure 400 utilizing light emitting nanostructures according to one embodiment. Many of the layers of the LED structure 400 share the same labels as the layers of the LED structure 100 and/or are functionally similar to the layers of the LED structure 100. For clarity, these layers will not be described again. According to one embodiment, the LED structure 400 includes a mixed layer 402 containing multiple different materials in the same layer. For example, the mixed layer 402 includes a hole transporting material, an electron transporting material, and a light emitting nanostructure. In this structure, hole generation, electron generation, and exciton formation all occur in the same mixed layer 402. The proximity of the light emitting nanostructure in the same layer as the formed exciton allows resonance energy transfer to occur between the light emitting nanostructure and the exciton.
The QD-LED mechanism based on resonance energy transfer described above in connection with fig. 2-4 has several advantages over direct charge injection. The high barrier to charge injection and low charge mobility within the QD-containing material layer do not limit device performance since electrons and holes, respectively, are no longer injected into the QDs. This allows a significant increase in the shell thickness of the QD without increasing the series resistance or on-voltage. For example, the (ZnSe/ZnS) shell thickness of InP core QDs can be increased by about 100-500%. The shell thickness may be between 1nm and 5 nm. To maintain efficient energy transfer between excitons and QDs, the shell thickness should not exceed 20nm, preferably should be less than 10 nm. In some embodiments, the shell material of the QDs comprises silica or alumina. The current-voltage characteristics of QD-LED devices according to embodiments of the present disclosure are largely independent of zinc selenide/zinc sulfide (ZnSe/ZnS) shell thickness. The current flowing through a QD-LED device depends on the mobility and the relative energy alignment (energetic alignment) of the hole transport layer and the electron transport layer. In addition, excitation of the QDs by exciton transfer will ensure that each QD core contains an equal number of electrons and holes. QD-LEDs based on resonant energy transfer will be more stable under continuous operation, since the degradation of QD-LEDs based on direct injection is generally due to auger recombination due to charge imbalance.
Fig. 5 illustrates a packaged LED device 500 according to an embodiment. The LED device 500 includes a layer stack 502, which may be any of the previously described layer stacks discussed with reference to fig. 2-4. The top conductive layer (anode or cathode) of the layer stack 502 may include a contact 504 and the bottom conductive layer (anode or cathode) of the layer stack 502 may include a contact 506. Each of contacts 504 and 506 may be a conductive material that includes leads 508 and 510, respectively, to carry electrical current. In some examples, contact 504 and/or contact 506 include a solder joint. In other examples, contact 504 and/or contact 506 represent planar metal films on which layer stack 502 is formed. Contacts 504 and 506 may be any conductive material that will form a good ohmic contact with the underlying layer. Example materials for contacts 504 and 506 include tin-based solder, aluminum, copper, and the like.
In one embodiment, the layer stack 502 is surrounded by an encapsulation material 512, which protects the layer stack 502 from the environment. The encapsulant 512 may be an epoxy that hardens to prevent oxygen and moisture from permeating through the epoxy. An encapsulation material 512 may also cover each of the contacts 504 and 506.
Fig. 6 illustrates an example method 600 of manufacturing a lighting device. The method 600 may be performed as part of a larger process for manufacturing a lighting device. Method 600 is not intended to be exhaustive and other steps may be performed without departing from the scope of the embodiments described herein. Further, the various steps of method 600 may be performed in a different order than that shown.
The method 600 begins at step 602, where step 602 is to provide a conductive substrate. The conductive substrate may be substantially transparent to visible light. The conductive substrate may include one or more conductive layers deposited on a non-conductive material. For example, the conductive substrate may comprise an ITO layer deposited on an underlying glass substrate. In one embodiment, the conductive substrate serves as an anode of the lighting device.
The method 600 continues with optional step 604, where step 604 is to deposit a hole injection layer on the conductive substrate. The hole injection layer may comprise poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (DEPOT-PSS). In some embodiments, the hole injection layer is spin coated to a final thickness of less than 100nm, less than 75nm, less than 50nm, less than 25nm, or less than 10 nm. After deposition onto the conductive substrate, the hole injection layer may be baked at a temperature between 150 ℃ and 250 ℃ for between 10 minutes and 20 minutes.
The method 600 continues with step 606, where step 606 is to deposit a hole transport layer over the hole injection layer (or over the conductive substrate if no hole injection layer is present). The hole transport layer may comprise TFB or NPB. In some embodiments, the hole transport layer is spin coated to a final thickness of less than 50nm, less than 25nm, less than 10nm, less than 5nm, or less than 1 nm. After deposition, the hole transport layer may be baked at a temperature between 150 ℃ and 200 ℃ for between 25 minutes and 35 minutes.
The method 600 continues with step 608 where step 608 is depositing a layer of material having light emitting nanostructures such that discontinuities are formed through the thickness of the layer of material. The light emitting nanostructures may comprise QDs with materials such as indium phosphide (InP), cadmium selenide (CdSe), and gallium arsenide (GaAs). In some embodiments, the material layer is spin coated to a final thickness of less than 10nm thick, less than 5nm thick, less than 1nm thick, or only a single monolayer thick. The material layer may be spin coated from an octane solution containing the light emitting nanostructures at a concentration between 15mg/mL to 0.5 mg/mL.
According to one embodiment, the final thickness of the material layer and the concentration of the light emitting nanostructures within the spin-coating solution may be adjusted to facilitate formation of discontinuities through the thickness of the material layer. The discontinuities may have any shape or pattern. In some examples, the discontinuities are randomly interspersed on the surface of the material layer. In other examples, the discontinuities are formed in a particular pattern, or encouraged to be formed using one or more application techniques, such as etching of a material layer.
The method 600 continues with step 610, where step 610 is to deposit an electron transport layer on the material layer. The electron transport layer can be spin coated from a solution of colloidal nanocrystals. The colloidal nanocrystals can comprise ZnMgO nanoparticles. In some embodiments, the electron transport layer is spin coated to a final thickness of less than 150nm, less than 125nm, less than 100nm, less than 75nm, less than 60nm, or less than 50 nm.
The electron transport layer contacts the hole transport layer via the discontinuities due to the presence of the discontinuities through the material layer. When the deposition of the electron transport layer on the material layer is also deposited within the discontinuities, contacts may be formed to contact the underlying hole transport layer.
The method 600 continues with step 612, where step 612 is to deposit a conductive layer on the electron transport layer. According to an embodiment, the conductive layer serves as a cathode of the lighting device. The conductive layers may include one or more conductive layers deposited on a non-conductive material. For example, the conductive layer may comprise an ITO layer deposited on an underlying glass substrate. The conductive layer may be substantially transparent to visible light. In another example, the conductive layer comprises one of aluminum, gold, or silver. The conductive layer can be deposited to a final thickness of less than 200nm, less than 175nm, less than 150nm, less than 125nm, less than 100nm, or less than 50 nm. In one embodiment, the conductive layer is deposited using thermal evaporation.
It should be understood that the order of the layers deposited in method 600 may be changed or reversed. For example, an electron transport layer may be first deposited on a conductive substrate, followed by the sequential deposition of a material layer and a hole transport layer. In such embodiments, the conductive substrate serves as the cathode and the conductive layer serves as the anode.
Exemplary embodiments of Quantum dots
As discussed in embodiments herein, a lighting device may include a layer of light emitting nanostructures. These light emitting nanostructures may comprise QDs, such as colloid-grown core-shell QDs.
Fig. 7 illustrates a cross-sectional structure of a barrier coated light emitting Nanostructure (NS)700 according to an embodiment. The barrier coated NS 700 includes an NS701 and a barrier 706. The NS701 includes a core 702 and a shell 704. The core 702 comprises a semiconductor material that emits light when absorbing higher energy. Examples of semiconductor materials for core 702 include indium phosphide (InP), cadmium selenide (CdSe), zinc sulfide (ZnS), lead sulfide (PbS), indium arsenide (InAs), indium gallium phosphide (InGaP), cadmium zinc selenide (CdZnSe), zinc selenide (ZnSe), and cadmium telluride (CdTe). Any other II-VI, III-V, ternary or quaternary semiconductor structure exhibiting a direct bandgap may also be used. In one implementation, the core 702 may also include one or more dopants such as metals, alloys, for example. Examples of the metal dopant may include, but are not limited to, zinc (Zn), copper (Cu), aluminum (Al), platinum (Pt), chromium (Cr), tungsten (W), palladium (Pd), or a combination thereof. The presence of one or more dopants in the core 702 may improve the structural and optical stability of the NS701, as well as the QY, compared to undoped NS.
According to one embodiment, the diameter dimension of the core 702 may be less than 20 nm. In another embodiment, the diameter dimension of the core 702 may be between about 1nm to about 5 nm. The ability to "tailor" the size of the core 702, and thus the size of the NS701, in the nanometer range allows for light emission coverage throughout the spectrum. Generally, a larger NS will emit light towards the red end of the spectrum, while a smaller NS will emit light towards the blue end of the spectrum. This effect occurs because larger NS levels are closer together than smaller NS. This allows the NS to absorb photons containing less energy, i.e., those closer to the red end of the spectrum.
A shell 704 surrounds the core 702 and is disposed on an outer surface of the core 702. The shell 704 may include cadmium sulfide (CdS), cadmium zinc sulfide (ZnCdS), selenium zinc sulfide (ZnSeS), and zinc sulfide (ZnS). In one embodiment, the shell 704 may have a thickness 704t, e.g., one or more monolayers. In other embodiments, the shell 704 may have a thickness 704t between about 1nm and about 5 nm. The shell 704 may be used to help reduce lattice mismatch with the core 702 and improve the QY of the NS 701. The shell 704 may also help passivate and remove surface trap states, such as dangling bonds, on the core 702 to increase the QY of the NS 701. The presence of surface trap states may provide non-radiative recombination centers and cause a reduction in the emission efficiency of the NS 701.
In alternative embodiments, the NS701 may include a second shell disposed on the shell 704, or more than two shells surrounding the core 702, without departing from the spirit and scope of the present invention. In one embodiment, the second shell may be on the order of two monolayers thick, and is typically, but not necessarily, also a semiconductor material. The second shell may provide protection for the core 702. The second shell material may be zinc sulfide (ZnS), although other materials may be used without departing from the scope or spirit of the invention.
The barrier layer 706 is configured to form a cladding layer on the NS 701. In one embodiment, the barrier layer 706 is disposed on the outer surface 704a of the shell 704 and is in substantial contact with the outer surface 704a of the shell 704. In embodiments of the NS701 having one or more shells, the barrier layer 706 may be disposed on the outermost shell of the NS701 and in substantial contact with the outermost shell of the NS 701. In an example embodiment, the barrier layer 706 is configured to act as a spacer between the NS701 and one or more NS, e.g., in a solution, composition, and/or film having a plurality of NS, wherein the plurality of NS may be similar to the NS701 and/or the NS 700 coated with the barrier layer. With such NS solutions, NS compositions, and/or NS films, barrier layer 706 can help prevent aggregation of NS701 with adjacent NS. Aggregation of NS701 with a neighboring NS may result in an increase in the size of NS701 and thus a decrease or quenching of the light emission properties of the aggregated NS (not shown) comprising NS 701. In further embodiments, the barrier layer 706 protects the NS701 from, for example, moisture, air, and/or harsh environments (e.g., high temperatures and chemicals used during photolithographic processing of the NS and/or during the manufacturing process of NS-based devices), which may adversely affect the structural and optical properties of the NS 701.
The barrier layer 706 comprises one or more amorphous, optically transparent and/or non-electroactive materials. Suitable barrier layers include inorganic materials such as, but not limited to, inorganic oxides and/or nitrides. Examples of materials for barrier layer 706 include oxides and/or nitrides of Al, Ba, Ca, Mg, Ni, Si, Ti, or Zr, according to various embodiments. In various embodiments, the barrier layer 706 may have a thickness 706t ranging from about 8nm to about 15 nm.
As illustrated in fig. 7, according to one embodiment, the NS 700 coated with a barrier layer may additionally or optionally include a plurality of ligands or surfactants 708. According to one embodiment, the ligand or surfactant 708 may be adsorbed or bound to the outer surface of the barrier coated NS 700, such as the outer surface of the barrier 706. The plurality of ligands or surfactants 708 can comprise a hydrophilic or polar head 708a and a hydrophobic or non-polar tail 708 b. Hydrophilic or polar head 708a may be bonded to barrier layer 706. The presence of the ligand or surfactant 708 may aid in separating the NS 700 and/or NS701 from other NS during their formation, e.g., in solution, composition, and/or membrane. The quantum efficiency of an NS, such as NS 700 and/or NS701, may be reduced if the NS is allowed to aggregate during its formation. Ligands or surfactants 708 may also be used to impart certain properties to the barrier-coated NS 700, such as hydrophobicity to provide miscibility in non-polar solvents, or to provide reactive sites for other compounds to bind (e.g., reverse micelle systems).
There are many ligands that can be used as ligand 708. In some embodiments, the ligand is a fatty acid selected from lauric acid, caproic acid, myristic acid, palmitic acid, stearic acid, and oleic acid. In some embodiments, the ligand is an organic phosphine or organic phosphine oxide selected from trioctylphosphine oxide (TOPO), Trioctylphosphine (TOP), Diphenylphosphine (DPP), triphenylphosphine oxide, and tributylphosphine oxide. In some embodiments, the ligand is an amine selected from the group consisting of dodecylamine, oleylamine, hexadecylamine, and octadecylamine. In some embodiments, the ligand is Trioctylphosphine (TOP). In some embodiments, the ligand is oleylamine. In some embodiments, the ligand is diphenylphosphine.
There are many surfactants that can be used as the surfactant 708. In some embodiments, a nonionic surfactant can be used as the surfactant 708. Some examples of nonionic surfactants include polyoxyethylene (5) nonylphenyl ether (trade name IGEPAL CO-520), polyoxyethylene (9) nonylphenyl ether (IGEPAL CO-630), octylphenoxy poly (ethyleneoxy) ethanol (IGEPAL CA-630), polyethylene glycol oleyl ether (Brij 93), polyethylene glycol cetyl ether (Brij 52), polyethylene glycol stearyl ether (Brij S10), polyoxyethylene (10) isooctylcyclohexyl ether (Triton X-100), and polyoxyethylene branched nonylcyclohexyl ether (Triton N-101).
In some embodiments, an anionic surfactant may be used as the surfactant 708. Some examples of anionic surfactants include sodium dioctyl sulfosuccinate, sodium stearate, sodium lauryl sulfate, sodium monododecyl phosphate, sodium dodecylbenzenesulfonate, and sodium myristyl sulfate.
In some embodiments, NS701 and/or 700 may be synthesized to emit light in one or more various color ranges, such as red, orange, and/or yellow ranges. In some embodiments, NS701 and/or 700 may be synthesized to emit light in the green and/or yellow range. In some embodiments, NS701 and/or 700 may be synthesized to emit light in the blue, indigo, violet, and/or ultraviolet ranges. In some embodiments, NS701 and/or 700 may be synthesized to have a dominant emission peak wavelength between about 605nm and about 650nm, between about 510nm and about 550nm, or between about 300nm and about 480 nm.
NS701 and/or 700 may be synthesized to have a high QY. In some embodiments, NS701 and/or 700 may be synthesized to have a QY between 80% and 95% or between 85% and 90%.
Thus, according to various embodiments, the NS 700 may be synthesized such that the presence of the blocking layer 706 on the NS701 does not substantially alter or quench the light emission properties of the NS 701.
Fig. 8 illustrates a cross-sectional view of an NS film 800 according to an embodiment. According to one embodiment, the NS film 800 may comprise a plurality of core-shell NS 700 (fig. 6) coated with a barrier layer and a matrix material 810. According to some embodiments, the NS 700 may be embedded or otherwise disposed in the matrix material 810. As used herein, the term "embedded" is used to indicate that the NS is enclosed or encased within a matrix material 810 that constitutes the main component of the matrix. It should be noted that in one embodiment, the NS 700 may be uniformly distributed throughout the matrix material 810, but in other embodiments, the NS 700 may be distributed according to an application-specific uniformity distribution function. It should be noted that even though the NS 700 are shown as having the same diameter size, one skilled in the art will appreciate that the NS 700 may also have a size distribution.
In one implementation, NS 700 may include a homogenous population of NS having a size that emits in the blue visible wavelength spectrum, in the green visible wavelength spectrum, or in the red visible wavelength spectrum. In other embodiments, the NS 700 may include a first NS population having a size that emits in a blue visible wavelength spectrum, a second NS population having a size that emits in a green visible wavelength spectrum, and a third NS population that emits in a red visible wavelength spectrum.
The matrix material 810 may be any suitable host matrix material capable of holding the NS 700. Suitable matrix materials may be chemically and optically compatible with NS 700 and any surrounding packaging materials or layers used in applying NS film 800 to a device. Suitable host materials may include non-yellowing optical materials that are transparent to both the primary and secondary light, thereby allowing both the primary and secondary light to be transmitted through the host material. In one embodiment, the matrix material 810 may completely surround each NS 700. In applications where a flexible or moldable NS film 800 is desired, the matrix material 810 may be flexible. Alternatively, the matrix material 810 may comprise a high strength non-flexible material.
The matrix material 810 may include polymers and organic and inorganic oxides. Suitable polymers for use in the matrix material 810 may be any polymer known to one of ordinary skill to be useful for such purposes. The polymer may be substantially translucent or substantially transparent. The matrix material 810 may include, but is not limited to: an epoxy resin; an acrylate; norbornene; polyethylene; poly (vinyl butyral); poly (vinyl acetate); a polyurea; a polyurethane; silicones and silicone derivatives including, but not limited to, Aminosilicones (AMS), polyphenylmethylsiloxanes, polyphenylalkylsiloxanes, polydiphenylsiloxanes, polydialkylsiloxanes, silsesquioxanes, fluorinated silicones, and vinyl and hydride substituted silicones; acrylic polymers and copolymers formed from monomers including, but not limited to, methyl methacrylate, butyl methacrylate, and lauryl methacrylate; styrene-based polymers such as polystyrene, Aminostyrene (APS) and poly (acrylonitrile styrene) (AES); polymers crosslinked with difunctional monomers such as divinylbenzene; a crosslinking agent suitable for crosslinking the ligand material; epoxides that combine with a ligand amine (e.g., an APS or PEI ligand amine) to form an epoxy resin; and the like.
In some embodiments, the matrix material 810 includes scattering microbeads, such as TiO, that can improve the light conversion efficiency of the NS film 8002Microbeads, ZnS microbeads or glass microbeads. In some embodiments, the matrix material 810 may include light blocking elements such as the light blocking elements 238 and/or 548 described above with reference to fig. 2-3 and 5.
In another embodiment, the matrix material 810 may have low oxygen and moisture permeability, exhibit high optical and chemical stability, exhibit a favorable refractive index, and adhere to the outer surface of the NS 700, thereby providing a hermetic seal to protect the NS 700. In another embodiment, the matrix material 810 may be cured with a UV or thermal curing process to facilitate roll-to-roll processing.
According to some embodiments, NS film 800 may be formed by mixing NS 700 in a polymer (e.g., photoresist) and casting an NS-polymer mixture on a substrate, mixing NS 700 with monomers and polymerizing them together, mixing NS 700 in a sol-gel to form an oxide, or any other method known to those skilled in the art.
According to some embodiments, the formation of the NS film 800 may include a film extrusion process. The film extrusion process may include forming a homogeneous mixture of the matrix material 810 and the barrier-coated core-shell NS, such as NS 700, and introducing this homogeneous mixture into a top-mounted hopper that feeds into the extruder. In some embodiments, the homogeneous mixture may be in the form of pellets. The film extrusion process may further include extruding the NS film 800 from a slot die and passing the extruded NS film 800 through a chill roll. In some embodiments, the extruded NS film 800 may have a thickness of less than about 75 μm, for example, a thickness in a range of about 70 μm to about 40 μm, about 65 μm to about 40 μm, about 60 μm to about 40 μm, or about 50 μm to about 40 μm. In some embodiments, NS film 800 has a thickness of less than about 10 μm. In some embodiments, the formation of the NS film 800 may optionally include a second process after the film extrusion process. The second process may include processes such as co-extrusion, thermoforming, vacuum forming, plasma treatment, molding, and/or embossing to provide texture to the top surface of the NS film 800. The textured top surface NS film 800 may help to improve, for example, defined optical diffusion properties and/or defined angular optical emission properties of the NS film 800.
An illumination device: example 1
A first example lighting device was prepared by forming various layers using a combination of spin coating and thermal evaporation. First, a hole injection material (PEDOT-PSS) was spin-coated to a thickness of about 50nm on an ITO substrate treated with UV-ozone and baked at 200 ℃ for 15 minutes. The device was transferred to an inert atmosphere and then a hole transport material (TFB) was deposited by spin coating to a final thickness of about 20nm and baked at 135 ℃ for 20 minutes. A monolayer of InP/ZnSe/ZnS QDs was then deposited by spin coating from a 9mg/mL octane solution. The QDs used in the present device contain a 3-4nm InP core with nominal shell compositions of 6.5ML ZnSe and 3ML ZnS. The QY of the InP/ZnSe/ZnS QD film was-40% when measured with the HTL/QD/ETL sandwich. After deposition of the QD layer, the ZnMgO electron transport layer was deposited by spin coating from a solution of colloidal nanocrystals to a final thickness of about 60 nm. An Al cathode was then deposited by thermal evaporation to a final thickness of about 150nm and the device was encapsulated using a glass lid, getter and epoxy.
Fig. 9A illustrates a data graph showing the External Quantum Efficiency (EQE) versus luminance for InP/ZnSe/ZnS QDs from the described first example illumination device. The maximum EQE achieved was 12.3%, significantly higher than any EQE previously reported for non-cadmium based QDs. Fig. 9B illustrates a data plot showing luminance versus applied voltage for the first example illumination device described. As a result of the efficient resonant energy transfer, the lighting device achieves a low on-voltage of about 1.5V.
An illumination device: example 2
A second example lighting device was prepared by forming various layers using a combination of spin coating and thermal evaporation. First, a hole injection material (PEDOT-PSS) was spin-coated to a thickness of about 50nm on an ITO substrate treated with UV-ozone and baked at 200 ℃ for 15 minutes. The device was transferred to an inert atmosphere and then a hole transport material (HT2310) was deposited by spin coating to a final thickness of about 25nm and baked at 170 ℃ for 30 minutes. A monolayer of InP/ZnSe/ZnS QDs was then deposited by spin coating from a solution of 0.09mg/mL octane. The QDs used in this device contain a 3-4nm InP core with nominal shell compositions of 6.5ML ZnSe and 3ML ZnS. The QY of the InP/ZnSe/ZnS QD film was-40% when measured with the HTL/QD/ETL sandwich. After deposition of the QD layer, the ZnMgO electron transport layer was deposited by spin coating from a solution of colloidal nanocrystals to a final thickness of about 60 nm. An Al cathode was then deposited by thermal evaporation to a final thickness of about 150nm and the device was encapsulated using a glass lid, getter and epoxy.
Fig. 10 provides an SEM taken of the second example illumination device after InP/ZnSe/ZnS QDs were deposited. The images show that the widely spaced individual QDs cover about 1% of the total pixel area due to the lower concentrations of QDs used in the octane solution. Instead of a continuous monolayer of QDs, each QD in the second example lighting device is surrounded by a hole transporting material and an electron transporting material (e.g., ZnMgO). Due to the efficiency of ZnMgO → QD energy transfer, the electroluminescence spectrum of the second example lighting device still consists almost entirely of QD emission, rather than parasitic emission from the electron transport layer.
It should be understood that the detailed description section is intended to be used to interpret the claims, and the summary and abstract sections are not. The summary and abstract sections may set forth one or more, but not all exemplary embodiments of the invention as contemplated by the inventors, and are therefore not intended to limit the invention and the appended claims in any way.
The invention has been described above with the aid of functional building blocks schematically illustrating the implementation of functions and relationships thereof. Boundaries of these functional components have been arbitrarily defined herein for convenience of description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.
The foregoing description of the specific embodiments reveals the general nature of the invention sufficiently that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the general concept of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein.
The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.

Claims (88)

1. An illumination device, comprising:
a first conductive layer;
a second conductive layer;
a hole transport layer disposed between the first conductive layer and the second conductive layer;
an electron transport layer disposed between the first conductive layer and the second conductive layer; and
a plurality of light emitting nanostructures disposed in a separate layer between the electron transport layer and the hole transport layer, the separate layer having a plurality of discontinuities through a thickness of the separate layer such that the hole transport layer and the electron transport layer are in contact with each other at the plurality of discontinuities, or the plurality of light emitting nanostructures disposed in the electron transport layer, or the plurality of light emitting nanostructures disposed in the hole transport layer, or the plurality of light emitting nanostructures disposed in a mixed layer comprising both the hole transport layer and the electron transport layer.
2. The lighting device of claim 1, wherein the plurality of light emitting nanostructures comprise a plurality of quantum dots.
3. The lighting device of claim 2, wherein the plurality of quantum dots comprises quantum dots having a core-shell structure, wherein the thickness of the core-shell structure shell is between 1 nanometer and 5 nanometers.
4. The lighting device of claim 3, wherein the plurality of quantum dots comprises quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
5. The lighting device according to any one of claims 1-4, wherein the separate layer has a thickness of one monolayer.
6. The lighting device of any one of claims 1-5, wherein the plurality of discontinuities form a random pattern.
7. The lighting device of any one of claims 1-5, wherein the plurality of discontinuities form a regular pattern.
8. The lighting device according to any one of claims 1-7, further comprising a hole injection layer disposed between the first conducting layer and the hole transport layer.
9. The lighting device of any one of claims 1-8, wherein the electron transport layer comprises a plurality of ZnMgO nanocrystals.
10. A quantum dot light emitting diode (QD-LED) device, the device comprising:
a layer stack comprising:
a first conductive layer formed on the first conductive layer,
a second conductive layer formed on the first conductive layer,
a hole transport layer disposed between the first conductive layer and the second conductive layer,
an electron transport layer disposed between the first conductive layer and the second conductive layer, and
a plurality of quantum dots, wherein the plurality of quantum dots are disposed in a separate layer between the electron transport layer and the hole transport layer, the separate layer having a plurality of discontinuities through a thickness of the separate layer such that the hole transport layer and the electron transport layer contact each other at the plurality of discontinuities, or the plurality of quantum dots are disposed in the electron transport layer, or the plurality of light emitting nanostructures are disposed in the hole transport layer, or the plurality of quantum dots are disposed in a mixed layer comprising both the hole transport layer and the electron transport layer;
a first contact coupled to the first conductive layer;
a second contact coupled to the second conductive layer; and
an encapsulation material configured to surround the layer stack.
11. The QD-LED device according to claim 10, wherein the encapsulation material comprises an epoxy.
12. The QD-LED device according to any one of claims 10 or 11, wherein the plurality of quantum dots comprises quantum dots having a core-shell structure, wherein the thickness of the core-shell structured shell is between 1nm and 5 nm.
13. The QD-LED device according to claim 12, wherein the plurality of quantum dots comprises quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
14. QD-LED device according to any of claims 10 to 13, wherein the individual layers have a thickness of one monolayer.
15. The QD-LED device according to any of claims 10 to 14, wherein the layer stack further comprises a hole injection layer disposed between the first conductive layer and the hole transport layer.
16. The QD-LED device according to any of claims 10-15, wherein the electron transport layer comprises a plurality of zinc magnesium oxide (ZnMgO) nanocrystals.
17. A method of forming a lighting device, the method comprising:
disposing a first material on a conductive substrate to form a first material layer, wherein the first material layer is configured as a hole transport layer or an electron transport layer;
disposing a layer of light emitting nanostructures on the first layer of material, wherein the layer of light emitting nanostructures includes one or more discontinuities in a thickness of the layer of light emitting nanostructures;
disposing a second material on the layer of light-emitting nanostructures to form a second material layer, wherein the second material is configured as an electron-transport layer or a hole-transport layer, and wherein the second material layer is in contact with the first material layer at the one or more discontinuities of the layer of light-emitting nanostructures; and
a conductive material is disposed on the second material layer.
18. The method of claim 17, wherein the disposing a layer of light emitting nanostructures comprises disposing a layer comprising a plurality of quantum dots.
19. The method of any one of claims 17 or 18, wherein the disposing a layer of light emitting nanostructures comprises disposing the layer using spin coating.
20. The method of any one of claims 17-19, wherein the disposing the second material comprises disposing a plurality of ZnMgO nanoparticles.
21. The method of any of claims 17-20, wherein the disposing the conductive substrate comprises disposing Indium Tin Oxide (ITO).
22. The method of any of claims 17-21, further comprising providing an encapsulant comprising an epoxy.
23. An illumination device, comprising:
a first conductive layer;
a second conductive layer;
a hole transport layer disposed between the first conductive layer and the second conductive layer;
an electron transport layer disposed between the first conductive layer and the second conductive layer; and
a separate layer comprising a plurality of light emitting nanostructures, the separate layer disposed between the electron transport layer and the hole transport layer, wherein the separate layer has a plurality of discontinuities through a thickness of the separate layer such that the hole transport layer and the electron transport layer contact each other at the plurality of discontinuities.
24. The lighting device of claim 23, wherein the plurality of light emitting nanostructures comprise a plurality of quantum dots.
25. The lighting device of claim 24, wherein the plurality of quantum dots comprise quantum dots having a core-shell structure, wherein the thickness of the core-shell structure shell is between 1 nanometer and 5 nanometers.
26. The lighting device of claim 25, wherein the plurality of quantum dots comprises quantum dots of which core material of the core-shell structure is indium phosphide (InP).
27. The lighting device according to any one of claims 23-26, wherein the separate layer has a thickness of one monolayer.
28. The lighting device of any one of claims 23-27, wherein the plurality of discontinuities form a random pattern.
29. The lighting device of any one of claims 23-28, wherein the plurality of discontinuities form a regular pattern.
30. The lighting device of any one of claims 23-29, further comprising a hole injection layer disposed between the first conducting layer and the hole transport layer.
31. The lighting device of any one of claims 23-30, wherein the electron transport layer comprises a plurality of ZnMgO nanocrystals.
32. An illumination device, comprising:
a first conductive layer;
a second conductive layer;
a hole transport layer disposed between the first conductive layer and the second conductive layer; and
an electron transport layer disposed between the first conductive layer and the second conductive layer and comprising a plurality of light emitting nanostructures.
33. The lighting device of claim 32, wherein the plurality of light emitting nanostructures comprise a plurality of quantum dots.
34. The lighting device of claim 33, wherein the plurality of quantum dots comprise quantum dots having a core-shell structure, wherein the thickness of the core-shell structure shell is between 1 nanometer and 5 nanometers.
35. The lighting device of claim 34, wherein the plurality of quantum dots comprise quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
36. The lighting device of any one of claims 32-35, further comprising a hole injection layer disposed between the first conducting layer and the hole transport layer.
37. The lighting device of any one of claims 32-36, wherein the electron transport layer further comprises a plurality of ZnMgO nanocrystals.
38. An illumination device, comprising:
a first conductive layer;
a second conductive layer; and
a mixed layer disposed between the first conductive layer and the second conductive layer, the mixed layer comprising an electron transporting material, a hole transporting material, and a plurality of light emitting nanostructures.
39. The lighting device of claim 38, wherein the plurality of light emitting nanostructures comprise a plurality of quantum dots.
40. The lighting device of claim 39, wherein the plurality of quantum dots comprise quantum dots having a core-shell structure, wherein the shell of the core-shell structure has a thickness between 1 nanometer and 5 nanometers.
41. The lighting device of claim 40, wherein the plurality of quantum dots comprise quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
42. The lighting device of any one of claims 38-41, further comprising a hole injection layer disposed between the first conducting layer and the hole transport layer.
43. The lighting device of any one of claims 38-42, wherein the electron transport layer comprises a plurality of ZnMgO nanocrystals.
44. A quantum dot light emitting diode (QD-LED) device, the device comprising:
a layer stack comprising:
a first conductive layer formed on the first conductive layer,
a second conductive layer formed on the first conductive layer,
a hole transport layer disposed between the first conductive layer and the second conductive layer,
an electron transport layer disposed between the first conductive layer and the second conductive layer, and
a separate layer comprising a plurality of quantum dots, the separate layer disposed between the electron transport layer and the hole transport layer, wherein the separate layer has a plurality of discontinuities through a thickness of the separate layer such that the hole transport layer and the electron transport layer contact each other at the plurality of discontinuities;
a first contact coupled to the first conductive layer;
a second contact coupled to the second conductive layer; and
an encapsulation material configured to surround the layer stack.
45. The QD-LED device according to claim 44, wherein the encapsulation material comprises an epoxy.
46. The QD-LED device according to claim 44 or 45, wherein the plurality of quantum dots comprises quantum dots having a core-shell structure, wherein the shell of the core-shell structure has a thickness between 1nm and 5 nm.
47. The QD-LED device according to claim 46, wherein the plurality of quantum dots comprises quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
48. The QD-LED device according to any of claims 44 to 47, wherein the individual layers have a thickness of one monolayer.
49. The QD-LED device according to any one of claims 44 to 48, wherein the plurality of discontinuities form a random pattern.
50. The QD-LED device according to any one of claims 44 to 48, wherein the plurality of discontinuities form a regular pattern.
51. The QD-LED device according to any of claims 44-45, wherein the layer stack further comprises a hole injection layer disposed between the first conductive layer and the hole transport layer.
52. The QD-LED device according to any of claims 44-51, wherein the electron transport layer comprises a plurality of zinc magnesium oxide (ZnMgO) nanocrystals.
53. A quantum dot light emitting diode (QD-LED) device, the device comprising:
a layer stack comprising:
a first conductive layer formed on the first conductive layer,
a second conductive layer formed on the first conductive layer,
a hole transport layer disposed between the first conductive layer and the second conductive layer, and
an electron transport layer disposed between the first conductive layer and the second conductive layer and comprising a plurality of quantum dots;
a first contact coupled to the first conductive layer;
a second contact coupled to the second conductive layer; and
an encapsulation material configured to surround the layer stack.
54. The QD-LED device according to claim 53, wherein the encapsulation material comprises an epoxy.
55. The QD-LED device according to claim 53 or 54, wherein the plurality of quantum dots comprises quantum dots having a core-shell structure, wherein the shell of the core-shell structure has a thickness between 1nm and 5 nm.
56. The QD-LED device according to claim 55, wherein the plurality of quantum dots comprises quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
57. The QD-LED device according to any of claims 53 to 56, wherein the layer stack further comprises a hole injection layer disposed between the first conductive layer and the hole transport layer.
58. The QD-LED device according to any of claims 53-57, wherein the electron transport layer comprises a plurality of zinc magnesium oxide (ZnMgO) nanocrystals.
59. A quantum dot light emitting diode (QD-LED) device, the device comprising:
a layer stack comprising:
a first conductive layer formed on the first conductive layer,
a second conductive layer, and
a mixed layer disposed between the first conductive layer and the second conductive layer, the mixed layer comprising an electron-transporting material, a hole-transporting material, and a plurality of quantum dots;
a first contact coupled to the first conductive layer;
a second contact coupled to the second conductive layer; and
an encapsulation material configured to surround the layer stack.
60. The QD-LED device according to claim 59, wherein the encapsulation material comprises an epoxy.
61. The QD-LED device according to claim 59 or 60, wherein the plurality of quantum dots comprises quantum dots having a core-shell structure, wherein the shell of the core-shell structure has a thickness between 1nm and 5 nm.
62. The QD-LED device according to claim 61, wherein the plurality of quantum dots comprises quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
63. The QD-LED device according to any of claims 59 to 62, wherein the layer stack further comprises a hole injection layer disposed between the first conductive layer and the hole transport layer.
64. The QD-LED device according to any of claims 59-63, wherein the electron transport layer comprises a plurality of zinc magnesium oxide (ZnMgO) nanocrystals.
65. A method of forming a lighting device, the method comprising:
disposing a first material on a conductive substrate to form a first material layer, wherein the first material layer is configured as a hole transport layer;
disposing a second material on the first material layer to form a second material layer, wherein the second material layer is configured as an electron transport layer, and wherein the second material layer comprises a plurality of light emitting nanostructures; and
a conductive material is disposed on the second material layer.
66. The method of claim 65, wherein the disposing the second material comprises disposing a second material comprising a plurality of quantum dots.
67. The method of claim 65 or 66, wherein the disposing the second material comprises disposing the second material using spin coating.
68. The method of any one of claims 65-67, wherein the disposing the second material includes disposing a plurality of ZnMgO nanoparticles.
69. The method of any of claims 65-68, wherein the disposing the conductive substrate comprises disposing Indium Tin Oxide (ITO).
70. The method of any of claims 65-69, further comprising providing an encapsulant comprising an epoxy.
71. A method of forming a lighting device, the method comprising:
disposing a mixed material layer on a conductive substrate, wherein the mixed material layer comprises an electron transport material, a hole transport material, and a plurality of light emitting nanostructures; and
a conductive material is disposed on the mixed material layer.
72. The method of claim 71, wherein the disposing the hybrid material layer comprises disposing a hybrid material layer comprising a plurality of quantum dots.
73. The method of claim 71 or 72, wherein the disposing the mixed material layer comprises disposing the mixed material layer using spin coating.
74. The method of any one of claims 71-73, wherein the disposing the mixed material layer comprises disposing a plurality of ZnMgO nanoparticles.
75. The method of any of claims 71-74, wherein the disposing the conductive substrate comprises disposing Indium Tin Oxide (ITO).
76. The method of any of claims 71-75, further comprising providing an encapsulant comprising an epoxy.
77. An illumination device, comprising:
a first conductive layer;
a second conductive layer;
a hole transport layer disposed between the first conductive layer and the second conductive layer and comprising a plurality of light emitting nanostructures; and
an electron transport layer disposed between the first conductive layer and the second conductive layer.
78. The lighting device of claim 77, wherein the plurality of light-emitting nanostructures comprise a plurality of quantum dots.
79. The lighting device of claim 78, wherein the plurality of quantum dots comprise quantum dots having a core-shell structure, wherein the shell of the core-shell structure has a thickness between 1 nanometer and 5 nanometers.
80. The lighting device of claim 79, wherein the plurality of quantum dots comprise quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
81. The lighting device of any one of claims 77-79, further comprising a hole injection layer disposed between the first conducting layer and the hole transport layer.
82. The lighting device of any one of claims 77-81, wherein the electron transport layer further comprises a plurality of ZnMgO nanocrystals.
83. A quantum dot light emitting diode (QD-LED) device, the device comprising:
a layer stack comprising:
a first conductive layer formed on the first conductive layer,
a second conductive layer formed on the first conductive layer,
a hole transport layer disposed between the first conductive layer and the second conductive layer and comprising a plurality of quantum dots, an
An electron transport layer disposed between the first conductive layer and the second conductive layer;
a first contact coupled to the first conductive layer;
a second contact coupled to the second conductive layer; and
an encapsulation material configured to surround the layer stack.
84. The QD-LED device according to claim 83, wherein the encapsulation material comprises an epoxy.
85. The QD-LED device according to claim 83 or 84, wherein the plurality of quantum dots comprise quantum dots having a core-shell structure, wherein the shell of the core-shell structure has a thickness between 1nm and 5 nm.
86. The QD-LED device according to claim 85, wherein the plurality of quantum dots comprises quantum dots of which the core material of the core-shell structure is indium phosphide (InP).
87. The QD-LED device according to any of claims 83 to 86, wherein the layer stack further comprises a hole injection layer disposed between the first conductive layer and the hole transport layer.
88. The QD-LED device of any one of claims 83-87, wherein the electron transport layer comprises a plurality of zinc magnesium oxide (ZnMgO) nanocrystals.
CN201980040310.7A 2018-05-11 2019-05-09 Quantum dot LED design based on resonance energy transfer Pending CN112352031A (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US201862670201P 2018-05-11 2018-05-11
US62/670,201 2018-05-11
US16/406,930 US11121339B2 (en) 2018-05-11 2019-05-08 Quantum dot LED design based on resonant energy transfer
US16/406,930 2019-05-08
PCT/US2019/031495 WO2019217662A1 (en) 2018-05-11 2019-05-09 Quantum dot led design based on resonant energy transfer

Publications (1)

Publication Number Publication Date
CN112352031A true CN112352031A (en) 2021-02-09

Family

ID=68464237

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201980040310.7A Pending CN112352031A (en) 2018-05-11 2019-05-09 Quantum dot LED design based on resonance energy transfer

Country Status (6)

Country Link
US (2) US11121339B2 (en)
EP (2) EP4166626A1 (en)
JP (2) JP2021523530A (en)
KR (1) KR102654434B1 (en)
CN (1) CN112352031A (en)
WO (1) WO2019217662A1 (en)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11121339B2 (en) * 2018-05-11 2021-09-14 Nanosys, Inc. Quantum dot LED design based on resonant energy transfer
EP3617292A1 (en) 2018-08-30 2020-03-04 Samsung Electronics Co., Ltd. Electronic device including quantum dots
US11380863B2 (en) * 2019-03-19 2022-07-05 Nanosys, Inc. Flexible electroluminescent devices
KR20210060706A (en) * 2019-11-18 2021-05-27 삼성디스플레이 주식회사 Quantum dots, compositions or composite including the same, patternized layer, and display device including the same
TW202230848A (en) * 2020-10-22 2022-08-01 美商納諾西斯有限公司 Electroluminescent devices with organic transport layers
TWI815330B (en) * 2021-03-18 2023-09-11 汯益光學股份有限公司 Stacked luminescent device and method of manufacturing the same
WO2024079909A1 (en) * 2022-10-14 2024-04-18 シャープディスプレイテクノロジー株式会社 Light-emitting element and display device
WO2024084572A1 (en) * 2022-10-18 2024-04-25 シャープディスプレイテクノロジー株式会社 Light-emitting element, display device, and method for forming light-emitting layer
WO2024084616A1 (en) * 2022-10-19 2024-04-25 シャープディスプレイテクノロジー株式会社 Light-emitting element, display device, and production method for light-emitting element
WO2024084617A1 (en) * 2022-10-19 2024-04-25 シャープディスプレイテクノロジー株式会社 Light-emitting element, display device, and method for manufacturing light-emitting element
CN115377263B (en) * 2022-10-25 2023-01-31 江西兆驰半导体有限公司 Epitaxial wafer for deep ultraviolet LED, preparation method of epitaxial wafer and deep ultraviolet LED

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102473800A (en) * 2009-07-07 2012-05-23 佛罗里达大学研究基金会公司 Stable and all solution processable quantum dot light-emitting diodes
CN105489782A (en) * 2016-01-18 2016-04-13 深圳市华星光电技术有限公司 Quantum dot light-emitting device and preparation method of quantum dot light-emitting device
CN205177887U (en) * 2015-11-10 2016-04-20 Tcl集团股份有限公司 Quantum dot emitting diode
CN105845833A (en) * 2016-04-07 2016-08-10 上海大学 White light quantum dot film electroluminescence device and manufacturing method thereof
CN105895813A (en) * 2016-04-07 2016-08-24 上海大学 Blue light quantum dot film electroluminescent device and preparation method thereof
CN106098956A (en) * 2016-07-14 2016-11-09 Tcl集团股份有限公司 A kind of QLED and preparation method thereof
CN106972110A (en) * 2017-05-02 2017-07-21 深圳市华星光电技术有限公司 Organic Light Emitting Diode component and preparation method thereof, display panel and electronic equipment

Family Cites Families (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2480518C (en) * 2002-03-29 2016-07-19 Massachusetts Institute Of Technology Light emitting device including semiconductor nanocrystals
JP2004172102A (en) * 2002-10-29 2004-06-17 Mitsubishi Chemicals Corp Electroluminescent element
KR20130007649A (en) 2005-02-16 2013-01-18 매사추세츠 인스티튜트 오브 테크놀로지 Light emitting device including semiconductor nanocrystals
JP2009087744A (en) * 2007-09-28 2009-04-23 Dainippon Printing Co Ltd Light-emitting element
JP2009199738A (en) * 2008-02-19 2009-09-03 Idemitsu Kosan Co Ltd Organic/inorganic hybrid type electroluminescent element
EP2576723B1 (en) 2010-05-27 2017-09-20 Merck Patent GmbH Compositions comprising quantum dots
KR101983229B1 (en) * 2010-07-23 2019-05-29 삼성디스플레이 주식회사 Organic light emitting device and method for manufacturing the same
EP2638321B1 (en) 2010-11-10 2019-05-08 Nanosys, Inc. Quantum dot films, lighting devices, and lighting methods
WO2012138409A2 (en) * 2011-04-02 2012-10-11 Qd Vision, Inc. Devices including quantum dots and method
JP2015076195A (en) * 2013-10-07 2015-04-20 パナソニックＩｐマネジメント株式会社 Organic electroluminescent element, method of manufacturing the same, and lighting device
JP2017068895A (en) * 2014-02-10 2017-04-06 パナソニックＩｐマネジメント株式会社 Organic electroluminescent device and luminaire
KR102292148B1 (en) * 2014-03-13 2021-08-24 가부시키가이샤 한도오따이 에네루기 켄큐쇼 Method for manufacturing display device and method for manufacturing electronic device
GB201407606D0 (en) * 2014-04-30 2014-06-11 Cambridge Entpr Ltd Electroluminescent device
KR102447309B1 (en) * 2015-12-24 2022-09-26 삼성디스플레이 주식회사 Light emitting diode and display device including the same
CN105428546A (en) * 2016-01-20 2016-03-23 京东方科技集团股份有限公司 QLED and preparing method thereof, and display device and preparing method thereof
CN105870346B (en) * 2016-04-15 2018-07-03 深圳市华星光电技术有限公司 The manufacturing method and LED display of LED display
CN105679958B (en) * 2016-04-20 2018-03-13 京东方科技集团股份有限公司 Electroluminescent device and preparation method thereof, display device
US20180119007A1 (en) * 2016-04-26 2018-05-03 Nanosys, Inc. Stable inp quantum dots with thick shell coating and method of producing the same
KR20190022689A (en) * 2016-06-27 2019-03-06 나노시스, 인크. Methods for buffered coating of nanostructures
CN106450013B (en) * 2016-10-11 2019-11-26 Tcl集团股份有限公司 QLED device
CN108550707B (en) * 2018-04-12 2022-11-08 京东方科技集团股份有限公司 Quantum dot light emitting diode and liquid crystal display device
US11121339B2 (en) * 2018-05-11 2021-09-14 Nanosys, Inc. Quantum dot LED design based on resonant energy transfer

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102473800A (en) * 2009-07-07 2012-05-23 佛罗里达大学研究基金会公司 Stable and all solution processable quantum dot light-emitting diodes
CN205177887U (en) * 2015-11-10 2016-04-20 Tcl集团股份有限公司 Quantum dot emitting diode
CN105489782A (en) * 2016-01-18 2016-04-13 深圳市华星光电技术有限公司 Quantum dot light-emitting device and preparation method of quantum dot light-emitting device
CN105845833A (en) * 2016-04-07 2016-08-10 上海大学 White light quantum dot film electroluminescence device and manufacturing method thereof
CN105895813A (en) * 2016-04-07 2016-08-24 上海大学 Blue light quantum dot film electroluminescent device and preparation method thereof
CN106098956A (en) * 2016-07-14 2016-11-09 Tcl集团股份有限公司 A kind of QLED and preparation method thereof
CN106972110A (en) * 2017-05-02 2017-07-21 深圳市华星光电技术有限公司 Organic Light Emitting Diode component and preparation method thereof, display panel and electronic equipment

Also Published As

Publication number Publication date
EP3775098B1 (en) 2022-12-14
KR102654434B1 (en) 2024-04-03
WO2019217662A1 (en) 2019-11-14
KR20210008016A (en) 2021-01-20
JP2024051110A (en) 2024-04-10
EP4166626A1 (en) 2023-04-19
US20190348623A1 (en) 2019-11-14
US20210408419A1 (en) 2021-12-30
US11121339B2 (en) 2021-09-14
EP3775098A1 (en) 2021-02-17
JP2021523530A (en) 2021-09-02

Similar Documents

Publication Publication Date Title
KR102654434B1 (en) Quantum dot LED design based on resonant energy transfer
US9680054B2 (en) Quantum dot light enhancement substrate and lighting device including same
US11637258B2 (en) Display devices with different light sources
US11296150B2 (en) Display devices with different light sources in pixel structures
US20210277307A1 (en) Blue-emitting nanocrystals with cubic shape and group iv metal fluoride passivation
US11985878B2 (en) Display devices with different light sources in pixel structures
US11380863B2 (en) Flexible electroluminescent devices
US20220209199A1 (en) Flexible electroluminescent devices
US20220131102A1 (en) Electroluminescent devices with hybrid transport layers
US20220131099A1 (en) Electroluminescent devices with organic transport layers

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
TA01 Transfer of patent application right
TA01 Transfer of patent application right

Effective date of registration: 20231019

Address after: Tokyo, Japan

Applicant after: SHOEI CHEMICAL Inc.

Address before: California, USA

Applicant before: NANOSYS, Inc.